Lever-type hoist and traction apparatus

Abstract: The invention relates to a lever-type hoist and traction apparatus in which an operation handle 18 is provided between a stopper 17 provided at the axial end portion of a driving shaft 5 and a driving member 8 screwed in the driving shaft 5 so as to be movable in the axial direction but unrotatable relatively to the driving shaft 5. A spring 19 for energizing the operation handle 18 toward the driving member 8 is provided to bring an inclined surface 31a of the engaging projection 31 provided on the operation handle 18 into elastic contact with an engaging stepped portion 37 of the driving member 8 during the time when the mechanical brake 13 is being operated, whereby the driving member 8 can be prevented from being reversely rotated with being accompanied by the returning operation of the operation lever 16 by the engaging resistance of the feed click 14 during the time when the hoist and traction is being conduction under the no-load condition.

Description: The present invention relates to a lever-type hoist and traction apparatus, in particular to a lever-type hoist and traction apparatus provided with an operation lever having a feed click and adapted to conduct a hoist and traction of loads by driving a load-sheave through a mechanical brake by a reciprocating operation of said operation lever. In a lever-type hoist and traction apparatus provided with an operation lever, as disclosed in for example Japanese Utility Model Application Laid-Open No. Hei 3-107490, the disclosure of which is hereby incorporaed by reference, a driving shaft is provided with a driving member having teeth on its outer periphery screwed therein. In addition, said operation lever is provided with a feed click engaged with said teeth of said driving member so as to be switched over, a click portion on the, feed side of the driving member being engaged with the teeth and the operation lever being reciprocally operated to forwardly screw the driving member, whereby operating a mechanical brake, a driving power due to a reciprocal operation of the operation lever being transmitted to a load-sheave from said driving shaft through said mechanical brake, and the load-sheave being driven to conduct a hoist and traction of loads. Furthermore a click portion on the return side of the feed click is engaged with the teeth of the driving member to reciprocally operate the operation lever, whereby rearwardly screwing the driving member and thus releasing the operation of the mechanical brake to reversely rotate the load-sheave by a quantity rearwardly screwed of the driving member in order to unload or release a traction. However, in said lever-type hoist and traction apparatus having the above described construction, the driving member is adapted to be regularly and reversely rotated by engaging one of the portion on the feed side and the return side of the feed click provided on the operation lever with the teeth provided on said outer periphery of the driving member and reciprocally operating the operation lever and the driving member is forwardly screwed by this regular rotation to operate the mechanical brake and transmit the driving power due to the reciprocal operation of the operation lever to the load-sheave from the driving shaft, whereby driving the load-sheave to be rotated, so that a disadvantage occurs in that in the case where no load is applied to the load-sheave, the driving member is forwardly screwed to operate the mechanical brake and consequently, even though the operation lever is reciprocally operated under this condition, the driving power is transmitted by a going movement of the operation lever and the operation lever is returned to a going movement-starting position without being followed by the driving member by a returning movement of the operation lever but in the case where the operation lever is reciprocally operated to operate the load-sheave in the hoist·traction direction under a no-load condition where no load is applied to the load-sheave, no-load is applied to the load-sheave, so that, even though the mechanical brake is operated during said going movement of the operation lever, an engaging resistance of the feed click engaged with the teeth of the driving member overcomes a reverse rotation resistance of the driving member to reversely rotate the mechanical brake with being accompanied by said returning movement of the operation lever, whereby releasing the mechanical brake and as a result, even though the operation lever is reciprocally operated, the driving member merely repeats the forward screwing·rearward screwing and thus the mechanical brake is not operated. So, conventionally, the operation lever is reciprocally operated with applying a load to the load-sheave or a load-chain laid on the load-sheave during the hoist·traction by means of the operation lever under the above described no-load condition or an external force is manually applied to the driving member from outside to prevent the driving member from being reversely rotated with being followed by the returning movement of the operation lever. However, in every case, a defect occurs in that an operation for applying a load to the load-sheave or said load-chain or an operation for applying said external force to the driving member is required in addition to the reciprocal operation of the operation lever, in particular in one-man working, an operation for adding the external force by one hand with operating the operation lever by the other hand and an operation for holding a hoist and traction apparatus body must be conducted and thus the hoist and traction operation under a no-load condition is complicated. EP 0 533 468 (Elephant Chain Block Company Limited) discloses a hoist and traction machine having a mechanical brake, in which an operating handle not-relative-rotatable is axially movably interposed between a stopper provided at an axial end of a driving shaft and a driving member screwable with the driving shaft, and between the operating handle and the stopper is provided regulation means having first and second regulation surfaces and for regulating a relative rotation range of the driving member with respect to the driving shaft so as to enable release of the regulation by moving the handle away from the driving member and a free rotation control surface in continuation of the second regulating surface, so that the operating handle is provided with engaging portions in elastic contact with the free rotation control surfaces and at the opposite surface of each projection with respect to the second regulation surface is provided a slanted guide surface. The operating handle is freely rotated in the normal direction so as to guide the projections toward the free rotation control surfaces and the driving member is moved away from a driven member by fee-rotation-operation of moving the operating handle from the driving member to be normally rotated, whereby the braking action of the mechanical brake by a braking ratchet wheel and braking plates is released to control the free rotation of the driving shaft and the elastic biasing member biases it to hold the state of free rotation control by the elastic contact of the projection. It is an object of the present invention to provide a lever-type hoist and traction apparatus capable of effectively operating a mechanical brake by a reciprocal operation of an operation lever without adding an external force during a hoist traction operation by means of said operation lever under a no-load condition to drivenly rotate a load-sheave in the hoist-traction direction by a simple operation. In order to achieve the above described object, the invention provides a lever-type hoist and traction apparatus as in claim 1. In addition, it is preferable that an end face in the axial direction of the engaging projection provided in the operation handle is engaged with said surface opposite to the operation handle of the driving member during a rotational operation of the operation handle relatively to the driving member, at least one projected portion having an idling-controlling surface brought into elastic contact by said energizing force of the spring being provided, and the or each said projected portion being provided with an engaging stepped portion at a rear end portion in a rotational direction thereof. Furthermore, it is preferable that an idling-controlling spring for energizing the driving member in the brake-loosening direction of the mechanical brake is provided between the driving member and the operation handle. Besides, it is preferable that the stopper is connected with the driving shaft by a connecting structure using a large number of concave and convex grooves concave portions and convex portions engaged with said concave portions being provided between opposite surfaces of the stopper and the operation handle, a plurality of at least ones of the concave portions and said convex portions being provided at regular intervals in the circumferential direction, and their pitch angles being selected so as to be different from those of said concave and convex grooves, provided between the stopper and the driving shaft and ones obtained by multiplying said pitch angles of the concave and convex grooves by integers. According to the present invention, said engaging stepped portion provided on the driving member is brought into elastic contact with the inclined surface of the engaging projection provided on the operation handle during the time when the mechanical brake is being operated, so that a force is given to the driving member in the brake-fastening direction at tire same time as a rotational resistance is given even under the no-load condition where no load is applied to the load-sheave. As a result, the driving member can be prevented from being reversely rotated with being accompanied by a returning operation of said operation lever by an engaging resistance of said feed click provided on the operation lever and engaged with teeth of the driving member during the time when the hoist and traction of the load-sieve is being conducted by the reciprocal operation of the operation lever. As a result, the mechanical brake can be always operated by operating the operation lever even under the no-load condition and thus the load-sheave can be drivenly rotated in the hoist traction direction through the mechanical brake. Consequently, in the case where the load-sheave is drivingly operated in the hoist·traction direction under the no-load condition, the conventional complicated operations for applying the load to the load-sheave and applying the external force to the driving member can be made unrequired and thus the hoist and traction operation under the no-load condition can be simplified. In addition, the end face of the engaging projection provided on the operation handle is engaged with the driving member and the projection having an idling-controlling surface brought into elastic contact by the energizing force of the spring is provided, whereby an idling condition can be held by bringing the projection into elastic contact with said idling-controlling surface by operating the operation handle and thus an input range of a tension of the load-chain during the idling-control can be expanded. As a result, the load-chain can be adjusted in length without requiring a skill. Furthermore, the engaging stepped portion is provided at the rear end portion in the drivenly rotating direction of the projection and the projection is brought into elastic contact with the inclined surface of the projection during the time when the mechanical brake is being operated, so that the hoist and traction operation by the reciprocal operation of the operation lever becomes possible by a simple construction utilizing the projection ever under the no-load condition. Moreover, the driving member can be rotated by an action of the idling-controlling spring to loosen the mechanical brake by the simple operation of merely drawing the operation handle to the outside position far from the driving member by providing the idling-controlling spring between the driving member and the operation handle . Consequently, even in the case where the idling operation is conducted by an inexperienced person, the idling operation can be easily achieved, the operatability being able to be improved, and the error operation being able to be eliminated, and thus also a disadvantage that the idling-controlling is impossible due to the error operation can be eliminated. Besides, the position where the inclined surface of the engaging projection provided on the operation handle is brought into elastic contact with the engaging stepped portion provided on the driving member when the inclined surface , is brought into elastic contact with the engaging stepped portion can be set to the suitable one, that is one near a top portion of the projection in the inclined surface , in high accuracy by merely adjusting the position of the operation handle in the circumferential direction relative to the stopper , in short by the simple operation of merely changing the engaging positions of the concave and convex portion, by providing a plurality of at least ones of the concave portions and the convex portions provided between the opposite surfaces of the stopper and the operation handle at regular intervals in the circumferential direction and selecting their pitch angles so as to be different from those of said concave and convex grooves connecting the stopper with the driving shaft and ones obtained by multiplying the pitch angles of the concave and convex grooves by integers. Additionally, the adjustment of this elastically contacting position can be easily achieved even though a lining plate of the mechanical brake is abraded and the elastically contacting position is our of order. The following description illustrates an embodiment of the invention. In the drawings:- Fig. 1 is a longitudinal sectional view showing one preferred embodiment of a lever-type hoist and traction apparatus according to the present invention; Fig. 2 is a perspective view as seen from an inside in the axial direction of an operation handle; Fig. 3 is a side view showing a relationship between said operation handle and a driving member; Fig. 4 is a front view showing a positional relationship between an engaging stepped portion of said driving member and an engaging projection of the operation handle during an ordinary use; Fig. 5 is a front view corresponding to Fig. 4 and showing a positional relationship during an idling-control; Fig. 6 is a longitudinal sectional view corresponding to Fig. 1 and showing said idling-control; Fig. 7 is an exploded perspective view showing principal members; Fig. 8 is a diagram showing a relationship between the operation handle and a stopper. A preferred embodiment shown in Fig. 1 relates to a lever-type hoist arid traction apparatus without an overload-preventing device. A cylindrical shaft 4 having a load-sheave 3 is rotatably supported between first and second side plates 1, 2 arranged oppositely at an appointed interval, a driving shaft 5, to which a rotary power is transmitted from the side of an operation lever described later, being relatively rotatably supported within said cylindrical shaft 4, and a reduction gear mechanism 6 comprising a plurality of reduction gears being provided between an outside end portion projected from said second side plate 2 of said driving shaft 5 and said load-sheave 3 to reducedly transmit said rotary power of the driving shaft 5 to the side of the load-sheave 3 by means of said reduction gear mechanism 6. In addition, a driven member 7 formed of a hub having a flange is screwed in an outside of the driving shaft 5 projected from said first side plate 1, a driving member 8 having teeth 8a on an outer periphery thereof being screwed in the driving shaft 5 on an outer side of said driven member 7, and a pair of brake plates 9, 10 and a brake click wheel 11 being provided between said driving member 8 and the driven member 7. Additionally, the first side plate 1 is provided with a brake click 12 to be engaged with said brake click wheel 11 and a mechanical brake 13 is composed of the brake click wheel 11 and the respective brake plates 9, 10. Furthermore, a feed click 14 provided with a click portion on the feed side and a click portion on the return side engageable with said teeth 8a provided on an outer circumferential portion of the driving member 8 is provided on an outer side in the radial direction of the driving member 8 in an outside portion of a brake cover 13a covering an outer circumferential portion of said mechanical brake 13 and an operation lever 16 provided with an operational portion 15 selectively engaging and deengaging with said click portion on the feed side and said click portion on the return side of said feed click 14 is provided. And, the driving shaft 5 is provided with a stopper 17 at an axial end portion thereof, an operation handle 18, which is unrotatable relatively to the driving shaft 5, is provided between said stopper 17 and the driving member 8 so as to be movable in the axial direction from a first position near the driving member 8 to a second position far from the driving member 8, a spring 19 mainly formed of a coil spring energizing the operation handle 18 toward the driving member 8 being provided between the operation handle 18 and the stopper 17, arid regulating means, which regulates a rotatable range of the operation handle 18 relatively to the driving shaft 5 of the driving member 8 and deregulates said rotatable range of the operation handle 18 relatively to the driving shaft 5 of the driving member 8 by a movement of the operation handle 18 in the direction far from the driving member 8, in short a movement toward the second position, being provided between the operation handle 18 and the driving member 8. That is to say, in said preferred embodiment shown in Fig. 1, the driving shaft 5 is provided with a ceration portion 23 having first and second screw portions 20, 21 and a large number of concave and convex grooves, the driven member 7 being screwed in said first screw portion 20 while the driving member 8 is screwed in said second screw portion 21, a coil spring 24 being provided between the driven member 7 and the driving member 8 to restrict a movement in the axial direction of the driven member 7 relative to the driving shaft 5, the driving member 8 being screwed in the leftward direction in Fig. 1 by regularly rotating the driving member 8 relatively to the driving shaft 5, said ceration portion 23 being engaged with a sleeve 25 on the outer side of the driving member 8, the stopper 17 being connected with an end portion of the ceration portion 23 on the outer side of said sleeve 25 by a connecting structure comprising a large number of concave and convex grooves, and the stopper 17 being fixedly mounted on the driving shaft 5 through the sleeve 25 by fastening a nut 27. Moreover, an engaging hole 28a provided in a boss portion 28 of the operation handle 18 is engaged with the sleeve 25, the operation handle 18 being provided between the stopper 17 and the driving member 8 under the condition that the driving shaft 5 is movable in the axial direction and rotatable, the operation handle 18 being provided with a pair of convex portions 29 on an inner circumferential surface thereof while the stopper 17 is provided with a pair of concave portions 30, with which said convex portions are to be engaged, on the outer circumferential portion thereof, and the convex portions 29 of the operation handle 18 being engaged with said concave portions 30 of the stopper 30 to make the operation handle 18 unrotatable relatively to the driving shaft 5. Besides, said spring 19 is provided between an outside surface of said boss portion 28 of the operation handle 18 and an inside surface opposite to the boss portion 28 of the stopper 17 to press the operation handle 18 in the direction toward the driving member 8 by an energizing power of the spring 19. Additionally, the boss portion 28 of the operation handle 18 is provided with two engaging projections 31 projecting toward the side of the driving member 8 at end portions in the radial direction on the rear surface side thereof symmetrically, as shown by a dotted line in Fig. 4, the driving member 8 being provided with a pair of projections 32 on the side opposite to the boss portion 28 of the operation handle 18 thereof symmetrically, as shown in Fig. 4, said projections 32 being provided with first and second regulating surfaces 33, 34 which are engaged with said engaging projections 31 to restrict said relative rotatable range of the driving member 8 relative to the driving shaft 5, whereby constructing said regulating means, when the driving member 8 is rotated relatively to the driving shaft 5, of said regulating surfaces 33, 34, said second regulating surface 34 positioned at a rear end portion in the regular rotation direction of the projections 32 being provided with an engaging stepped portion 37 with which said engaging projection 31 is to be engaged, an inclined surface 31a inclined rear outward in the regular rotation direction of the driving member 8 toward a base end side from a front end side of the projection 31 being provided on the front side in the regular rotation direction of the driving member 8 in the projection 31, as shown in Figs. 2, 3, and said inclined surface 31 being brought into elastic contact with said engaging stepped portion 37 by an energizing force in the axial direction of the spring 19 under the condition that the mechanical brake 13 is being operated, in short the driving member 8 is being forwardly screwed to operate the mechanical brake 13. In addition, in the preferred embodiment shown in the drawings, an idling-controlling spring 50 for energizing the driving member 8 in the brake-loosening direction of tile mechanical brake 13 is provided between the driving member 8 and the operation handle 18, the projection 32 being provided with an idling-controlling surface 35 which is continual from the second regulating surface 34 and moves the operation handle 18 to the second position far from the driving member 8 to rotate the driving member 8 relatively to the driving shaft 5 by an energizing force in the return direction of said idling-controlling spring 50, whereby bringing a projected front end surface of the engaging projection 31 into proximity with the driving shaft 5 by energizing the spring 19 in the axial direction when the mechanical brake 13 was loosened and thus gives a rotary resistance to the driving member 8 to hold an idling rotation, and the projection 32 being provided with a third regulating surface 36, which rises from said idling-controlling surface 35 and is engaged with the front side in the rotary direction of the engaging projection 31 when the driving member 8 is rotated relatively to the driving shaft 5 under the condition that the front end surface of the engaging projection 31 is brought into contact with the idling-controlling surface 35, as shown in Figs. 1, 7. Furthermore, referring to Fig. 1, reference numeral 44 designates a click-holding mechanism holding the feed click 14 at three positions, that is a feed position (regularly rotating position) where the click portion on the feed side of the feed click 14 is engaged with the teeth 8a of the driving member 8, a return position (reversely rotating position) where the click portion on the return side is engaged with the teeth 8a and a neutral position where neither of the click portion on the feed side and the click portion on the return side is engaged with the teeth 8a, said click-holding mechanism 44 comprising a pressing member 45 and a spring 46, and letters, such as for example feed , return and neutral or idling , being displayed on an outer surface of the operation lever 16 for indicating the operating positions of said operational portion 15 of the feed click 14. Moreover, although the driving shaft 5 is provided with the first- and second screw portions 20, 21 thereon to screw the driven member 7 and the driving member 8 therein taking the workability and strength of the driving shaft into consideration in the above described construction, also a ceration may be used as the first screw portion 20. In addition, although, in the case where the driven member 7 is screwed by providing the first screw portion 20, the forward screwing of the driven member 7 is restricted by means of the coil spring 24, the second screw portion 21 may be provided with an E-ring to provide the coil spring 24 between said E-ring and the driven member 7. Furthermore, tapped grooves of the first screw portion 20 may be coated with nylon resins having an increased elastic repulsion and a frictional splicing force made by U.S. Nylock, Inc. to restrict the forward screwing of the driven member 7 by a return-preventing effect thereof. Besides, the driven member 7 may be fixedly mounted on the driving shaft 5 by screwing or striking a cotter pin and thus the spring 24 is not required. An operation of the lever-type hoist and traction apparatus having the above described construction will be below described. At first, in case of a loading operation, the click portion on the feed side of the feed click 14 is engaged with the teeth 8a of the driving member 8 by operating the operational portion 15 provided on the operation lever 16 to reciprocally operate the operation lever 16, whereby rotating the driving member 8 in the regularly rotating direction. At this time, if the load is applied to the load-sheave 3, the driving member 8 is screwed in the leftward direction in Fig. 1, that is to the side of the driven member 7, and this forward screwing condition is maintained to operate the mechanical brake 13. On the other hand, in the case where no load is applied to the load-sheave 3, in the conventional examples, the driving member 8 is reversely rotated with the return movement of the lever 16 if the engaging resistance of the click portion on the feed side engaged with the teeth 8a is larger than the reverse rotating resistance of the driving member 8 during the return movement of the lever 16 and thus the mechanical brake 13 cannot be operated even though the lever 16 is reciprocally operated. However, according to the present invention, when the mechanical brake 13 is operated by the rotation of the driving member 8 resulting from the going movement of the lever 16, the engaging stepped portion 37 is brought into elastic contact with the inclined surface 31a of the engaging projection 31 of the operation handle 18 to act the energizing force in the axial direction of the spring 19 upon the driving member 8, whereby pressing the driving member 8 inward (toward the load-sieve) in the axial direction. As a result, a resistance is given to the reverse rotation of the driving member 8 and simultaneously the engaging stepped portion 37 is brought into elastic contact with the inclined surface 31a, so that a force component rotating the driving member 8 in the brake-fastening direction acts upon the driving member 8 by the energizing force of the spring 19 to give the reverse rotating resistance larger than the engaging resistance by the feed click 14 to the driving member 8. Consequently, even under the no-load condition where no load is applied to the load-sheave 3, after the driving member 8 was forwardly screwed by the going movement of the lever 16, the driving member 8 is not reversely rotated to be rearwardly screwed even the returning movement operation is conducted, and as a result, the forward screwing of the driving member 8 is maintained and thus the mechanical brake 13 is operated. And, by the action of the mechanical brake 13, the rotary power of the, driving member 8 resulting from the going movement operation of the operation lever 16 is transmitted to the side of the load-sheave 3 through the reduction gear mechanism 6 and the cylindrical shaft 4 from the driving shaft 5 and the baggages and the like connected with the chain laid around the load-sheave 3 are loaded. On the other hand, in case of an unloading operation, the click portion on the return side of the feed click 14 in the operational portion 15 is engaged with the teeth 8a of the driving member 8 to swingably operate the lever 16, whereby rotating the driving member 8 in the reverse rotating direction. As a result, the driving member 8 is screwed rearwardly relatively to the driven member 7 and thus the braking action of the mechanical brake 13 is stopped to be capable of reversely rotating the driving shaft 5 by the quantity of the reverse rotation of the driving member 8 and thus the unloading operation can be safely conducted. The case where said chain laid around the load-sheave 3 is freely lengthened and shortened to the load side under the idling condition of the load-sheave 3 will be below described. In this case, the feed click 14 is positioned at the neutral position and the operation handle 18 is drawn to the side of the stopper 17, that is the second position far from the driving member 8, against the energizing force in the axial direction of the spring 19 under this condition. As a result, the projection 31 provided on the operation handle 18 is moved to a regulation-releasing position which is not regulated by the first- and second regulating surfaces 33, 34. By this regulation-releasing and the switching of the feed click 14 to the neutral position, the driving member 8 is rotated in the brake-loosening direction (the direction shown by a dotted line in Fig. 4) by the enegizing force in the twisting direction of the idling-controlling spring 50 to take the condition shown in Fig. 5. Consequently, by merely using the spring force of the spring 50 as the spring force capable of rotating the driving member 8 to the brake-loosening position to draw the operation handle 18 to the second position, the driving member 8 can be rotated to be rearwardly screwed in the direction far from the driven member 7, the braking action by the mechanical brake 13 being capable of being cancelled, and the load-sheave 3 being capable of being brought under the idling condition. Moreover, at this time, the projection 31 is moved to the position shown by a dotted line in Fig. 5 from the position shown by a dotted line in Fig. 4 to be opposite to the idling-controlling surface 35 of the driving member 8 and when the drawing operation of the operation handle 18 is released under this condition, the operation handle 18 is pressed toward the driving member 8 by the energizing force in the axial direction of the spring 19 and the projected front end surface of the projection 31 is brought into elastic contact with the idling-controlling surface 35 of the projection 32 provided on the driving member 8, as shown in Fig. 6, whereby the idling rotation condition of the load-sheave 3 is held by the frictional resistance resulting from this elastic contact. Consequently, during the idling rotation when the chain is pulled to speedily lengthen and shorten the chain on the load side, the input range of the tension of the chain can be expanded as compared with that in the conventional examples and the chain on the load side can be lengthened and shortened without requiring a skill. In addition, when the tension of the chair, is enhanced under the above described idling-controlling condition and the strong force is acted upon the load-sheave 3 in the reverse rotating direction, the elastic contact of the projected front end surface of the engaging projection 31 with the idling-controlling surface 35 is slippedly released to return the engaging projection 31 between the first regulating surfae 33 and the second regulating surface 34, whereby the condition that the braking operation of the mechanical brake 13 can be conducted and suspended, as above described, is recovered. That is, when the strong force is acted upon the load-sheave 3 in the reverse rotating direction, the driving member 8 is screwed in the driving shaft 5 and its rotary inertia is large as compared with that of the driving shaft 5, so that the idling-controlling surface 35 overcomes the twisting energizing force of the spring 19 to be slipped relatively to the engaging projection 31, whereby the driving member 8 begins to start to rotate slightly behind the rotation of the operation handle 18. As a result, the elastic contact of the projected front end surface of the engaging projection 31 with the idling-controlling surface 35 is released to return the engaging projection 31 between the first regulating surface 33 and the second regulating surface 34. Furthermore, in the case where the load-sheave 3 is adjusted in length by controlling the idling in the above described manner to conduct the loading and the traction, the feed click 14 is switched over to the feed position from the neutral position to engage the click portion on the feed side with the teeth 8a and operate the operation lever 16, whereby the mechanical brake 13 can be easily returned to the operating condition. That is to say, when the operation lever 16 is operated under the condition that the click portion on the feed side is engaged with the teeth 8a, the rotary resistance is given to the driving shaft 5 by the strained load-chain, so that the driving member 8 is rotated in the regular rotating direction, in short in the feed direction, to be rearwardly screwed, whereby the mechanical brake 13 is operated and the load-sheave 3 is rotated through the mechanical brake 13 and as a result, the hoist and traction can be conducted. Besides, in the above described preferred embodiment, in order to install the operation handle 18 and the stopper 17, the driving member 8 is screwed in the driving shaft 5, the mechanical brake 13 being fastened to be brought under the operating condition, and the click portion on the feed side of the feed click 14 of the operation lever 16 installed in advance being engaged with the teeth 8a of the driving member 8, followed by engaging the sleeve 25 with the ceration portion 23 of the driving shaft 5, engagedly inserting the engaging hole 28a of the boss portion 28 in the operation handle 18 into the sleeve 25, positioning the inclined surface 31a in the engaging projection 31 of the handle 18 so as to be brought into elastic contact with the engaging stepped portion 37 of the driving member 8 in the vicinity of the top portion of the projection 31, engaging the stopper 17 with the ceration portion 23 with holding this condition and adjusting so that the concave portion 30 of the stopper 17 may coincide with the convex portion 29 of the operation handle 18, and fastening the nut 27 to fixedly mount the stopper 17 on the driving shaft 5. By the way, in the above described construction, if the pitch angles of the concave and convex grooves of the ceration portion 23 and the concave and convex grooves to be engaged with the concave and convex grooves of the ceration portion 23 of the stopper 17 are reduced, even through the concave and convex grooves of the stopper 17 are shifted from the concave and convex grooves of the ceration portion 23 when the concave portion 30 of the stopper 17 is coincidedly engaged with the convex portion 29 of the operation handle 18 held at the above described elastic contact position, one pitch angle of the respective concave and convex grooves is largest, so that the quantity of the shift of the position of elastic contact of the inclined surface 31a in the projection 31 with the engaging stepped portion 37 is not increased but in the case where the pitch angles of the concave and convex grooves are set at for example 15 to 20°, that is the number of the concave and convex grooves 17a of the stopper 17 and the concave and convex grooves 23a of the ceration portion 23 is set to 18, respectively, as shown in Fig. 8, the maximum shift of the elastic contact position corresponding to 20° is brought about. Consequently, the force component in the brake-fastening direction of the driving member 8 by the spring 19 is reduced by this shift and the reverse rotary resistance larger than the engaging resistance by the feed click 14 can not be given to the driving member 8 under certain circumstances but the shift of the elastic contact position can be easily eliminated by providing a plurality of at least ones of the concave portions 30 and said convex portions 29 at regular intervals in the circumferential direction and selecting the pitch angles so as to be different from those of said concave and convex grooves 17a, 23a provided on the stopper 17 and the ceration portion 23 of the driving shaft 5 and ones obtained by multiplying the pitch angles of the concave and convex grooves 17a, 23a by integers. That is to say, in the preferred embodiment shown in Fig. 8, tire pitch angles  1 of the concave and convex grooves 17a, 23a provided on the stopper 17 and the ceration portion 23 are set at 20°, a pair of convex portions 29 shifted in phase by 180° being provided on the operation handle 18, and the stopper 17 being provided with 8 concave portions 30, with which the convex portions 29 are to be engaged, at the pitch angles  2 of 45° in the circumferential direction. Consequently, the position of the operation handle 18 relative to the stopper 17 in the circumferential direction can be shifted by 5° by shifting the position, where the concave portions 30 are engaged with the convex portions 29, by one pitch angle  2 , that is 45°, under the condition that the stopper 17 is shifted relatively to the ceration portion 23 of the driving shaft 5 by two pitch angles 2  1 , that is 40°. In addition, the position of the operation handle 18 relative to the stopper 17 in the circumferential direction can be shifted by 10° by shifting the position, where the concave portions 30 are engaged with the convex portions 29, by two pitch angles 2  2 , that is 90°, under the condition that the stopper 17 is shifted relatively to the ceration portion 23 of the driving shaft 5 by four pitch angles 4  1 , that is 80°. Furthermore, the position of the operation handle 18 relative to the stopper 17 in the circumferential direction can be shifted by three pitch angles 3  2 , that is 135°, by shifting the position, where the concave portions 30 are engaged with the convex portions 29, by six pitch angles 6  1 , that is 120°, under the condition that the stopper 17 is shifted relatively to the ceration portion 23 of the driving shaft 5 by six pitch angles 6  1 , that is 120°. That is to say, the position of the operation handle 18 relative to the stopper 17 in the circumferential direction can be adjusted to 3 steps of 5°, 10° and 15°. Besides, the pitch angles of the concave and convex grooves 17a, 23a of the stopper 17 and the ceration portion 23 are not limited by the above described 20° but they may be set to for example 15°. In the case where the pitch angles of the concave and convex grooves 17a, 23a are set to 15°, the pitch angles of the concave portions 30 provided in the stopper 17 are set differently from not only ones of 15° but also ones obtained by multiplying 15° by integers. That is to say, they are set to for example 36°. In this case, the position of the operation handle 18 relative to the stopper 17 in the circumferential direction can be adjusted at four steps of 0°, 3°, 6° and 9°. In addition, in the preferred embodiment shown in Fig. 8. a plurality of concave portions 30 were provided in the stopper 17 at the pitch angles selected so as to be different from the pitch angles of the concave and convex grooves and ones obtained by multiplying the pitch angles of the concave and convex grooves by integers but a plurality of convex portions 29 may be provided in the operation handle 18 at the pitch angles selected so as to be different from the pitch angles of the concave and convex grooves and ones obtained by multiplying the pitch angles of the concave and convex grooves by integers. Furthermore, the operation handle 18 was provided with the convex portions 29 and the stopper 17 was provided with the concave portions 30 but the operation handle 18 may be provided with the concave portions 30 and the stopper 17 may be provided with the convex portions 29. Besides, in the case where the above described construction is adopted, in order to install the operation handle 18 and the stopper 17, the same method as the above described one is used but the operation handle 18 is positioned so that the inclined surface 31a in the engaging projection 31 of the handle 18 may be brought into elastic contact with the engaging stepped portion 37 of the driving member 8 at the vicinity of the top portion thereof and the concave portion 30 of the stopper 17 nearest the convex portion 29 of the operation handle 18 is engaged with the convex portion 29 under the above described condition held to install the stopper 17 in the ceration portion 23 of the driving shaft 5. In this case, if the concave portion 30 is shifted relative to the convex portion 29 in position, the stopper 17 is rotated by every 2 pitch angles of the concave and convex grooves 17a to be adjusted, whereby being engaged under the nearest condition. As a result, the position of the operation handle 18 relative to the driving member 8, in short the position where the inclined surface 31a is brought into elastic contact with the engaging stepped portion 37, can be set at the optimal position in the vicinity of the top portion or positions near the optimal position and thus the elastic contact position can be accurately and simply determined, whereby the installability can be improved. In addition, even in the case where the braking plates 9, 10 and the like in the mechanical brake 13 were abraded, the adjustment cart be easily conducted by changing the position of the stopper 17 relative to the operation handle 18 in the above described installing procedure under the condition that the operation handle 18 is positioned at the proper elastic contact position and also the readjustment can be simply conducted. Although the operation handle 18 is energized in the axial direction by means of the spring 19 and the driving member 8 is energized in the brake-loosening direction by means of the idling-controlling spring 50 in the above described preferred embodiment, the idling-controlling spring 50 may be omitted to merely energize the operation handle 18 in the axial direction by means of the spring 19. In addition, in the case where the idling-controlling spring 50 is used, the coil spring may be used as the idling-controlling spring 50 but the flat spring is preferably used, as shown in Figs. 1, 7. That is to say, the idling-controlling spring 50 shown in Figure 1 comprises a twisted portion 50a that is twisted spirally so as to lie in one plane in the mechanism as shown in Figure 1. First and second spring legs 50b, 50c (Figure 7) are positioned at respective ends of said twisted portion, said first spring leg 50b being bent at right angles so as to extend in an axial direction relative to the plane of the twisted portion 50a as viewed in Figure 1 to allow it to engage with the first regulating surface 33 of the driving member 8, and the second spring leg 50c being bent in the radial plane of the twisted portion 50a as shown in Figure 1 to be engaged with the front surface of the engaging projection 31 of the operation handle 8 as may be seen in Figure 7, that is, the front surface in the regular rotating direction of the driving member. Furthermore, although the driving member 8 is formed of the single member to be screwed in the driving shaft 5 in the above described preferred embodiment, the driving member 8 may comprise a brake-pressing member scrweed in the driving shaft 5 and a body of revolution rotatably supported on a cylindrical portion of said brake-pressing member and provided with teeth on an outer circumference thereof. In this case, a lining plate is provided between the brake-pressing plate and said body of revolution, said lining plate and a flat spring being supported on the brake-pressing member outside of the body of revolution, and a load-setting and adjusting member being scrweed to compose an overload-preventing mechanism. In the case where said overload-preventing mechanism is incorporated in such the manner, the same shape as the projection 32 is given to said load-setting and adjusting member and the load-setting and adjusting member is provided with the first- and second regulating surfaces 33, 34 and the idling-controlling surface 35 to form the engaging stepped portion 37 at the end portion of the second regulating surface 34. In addition, in the present preferred embodiment, the driving member means the whole overload-preventng mechanism including the brake-pressing member and the load-setting and adjusting member and the member, on which the engaging stepped portion 37 is to be provided, is not limited by the load-setting and adjusting member but the engaging member may be provided on the brake-pressing member or a member fixedly mounted on the brake-pressing member. Furthermore, in the case where the idling-controlling spring energizing the driving member in the brake-loosening direction is provided, the spring leg of this spring may be engaged with the load- setting and adjusting member or the brake-pressing member or said member fixedly mounted on the brake-pressing member. Furthermore, in the case where the idling-controlling spring is provided, the flat spring shown in Figs. 1, 7 is preferably used. Besides, according to the present invention, although it is preferable that the driving member 8 is provided with the idling-controlling surface 35 so that the engaging projection 31 may be brought into elastic contact with the idling-controlling surface 35 to hold the idling condition, it is not indispensable. According to the present invention, said engaging stepped portion 37 provided on the driving member 8 is brought into elastic contact with the inclined surface 31a of the engaging projection 31 provided on the operation handle 18 during the time when the mechanical brake 13 is being operated, so that a force is given to the driving member 8 in the brake-fastening direction at the same time as a rotational resistance is given even under the no-load condition where no load it applied to the load-sheave 3. As a result, the driving member 8 can be prevented from being reversely rotated with being accompanied by a returning operation of said operation lever 16 by an engaging resistance of said feed click 14 provided on the operation lever 16 and engaged with teeth 8a of the driving member 8 during the time when the hoist and traction of the load-sheave 3 is being conducted by the reciprocal operation of the operation lever 16. As a result, the mechanical brake 13 can be always operated by operating the operation lever 16 even under the no-load condition and thus the load-sheave 3 can be drivenly rotated in the hoist·traction direction through the mechanical brake 13. Consequently, in the case where the load-sheave 3 is drivenly operated in the hoist·traction direction under the no-load condition, the conventional complicated operations for applying the load to the load-sieve and applying the external force to the driving member can be made unrequired and thus the hoist and traction operation under the no-load condition can be simplified. In addition, the end face of the engaging projection 31 provided on the operation handle 18 is engaged with the driving member 8 and the projection 32 having an idling-controlling surface 35 brought into elastic contact by the energizing force of the spring 19 is provided, whereby an idling condition can be held by bringing the projection 31 into elastic contact with said idling-controlling surface 35 by operating the operation handle 18 and thus an input range of a tension of the load-chain during the idling-control can be expanded. As a result, the load-chain can be adjusted in length without requiring a skill. Furthermore, the engaging stepped portion 37 is provided at the rear end portion in the drivenly rotating direction of the projection 32 and the projection 37 is brought into elastic contact with the inclined surface 31a of the projection 31 during the time when the mechanical brake 13 is being operated, so that the hoist and traction operation by the reciprocal operation of the operation lever becomes possible by a simple construction utilizing the projection 32 even under the no-load condition. Moreover, the driving member 8 can be rotated by an action of the idling-controlling spring 50 to loosen the mechanical brake 13 by the simple operation of merely drawing the operation handle 18 to the outside position far from the driving member 8 by providing the idling-controlling spring 50 between the driving member 8 and the operation handle 18. Conseuqntly, even in the case where the idling operation is conducted by an inexperienced person, the idling operation can be easily achieved, the operatability being able to be improved, and the error operation being able to be eliminated, and thus also a disadvantage that the idling-controlling is impossible due to the error operation can be eliminated. Besides, the position where the inclined surface 31a of the engaging projection 31 provided on the operation handle 18 is brought into elastic contact with the engaging stepped portion 37 provided on the driving member 8 when the inclined surface 31a is brought into elastic contact with the engaging stepped portion 37 cart be set to the suitable one, that is one near a top portion of the projection 31 in the inclined surface 31a, in high accuracy by merely adjusting the position of the operation handle 18 in the circumferential direction relative to the stopper 17, in short by the simple operation of merely changing the engaging positions of the concave and convex portions 29, 30, by providing a plurality of at least ones of the concave portions 30 and the convex portions 29 provided between the opposite surfaces of the stopper 17 and the operation handle 18 at regular intervals in the circumferential direction and selecting their pitch angles so as to be different from those of said concave and convex grooves 17a, 23a connecting the stopper 17 with the driving shaft 5 and ones obtained by multiplying the pitch angles of the concave and convex grooves 17a, 23a by integers. Additionally, the adjustment of this elastically contacting position can be easily achieved even though a lining plate of the mechanical brake 13 is abraded and the elastically contacting position is out of order.

Claims: A lever-type hoist and traction apparatus comprising a load-sheave (3), a driving shaft (5) having a driven member (7) for driving said load-sheave (3), a driving member (8) provided with teeth (8a) on an outer periphery thereof and screwed in said driving shaft (5), and an operation lever (16) provided with a mechanical brake (13) and a feed click (14) switchably engaged with said teeth (8a) for driving said driving member (8) in regular and reverse directions by a reciprocal operation whereby rotation in the regular direction operates the mechanical brake, further comprising a stopper (17) provided at an axial end portion of the driving shaft (5), an operation handle (18) movable in the axial direction but unrotatable relatively to the driving shaft (5) and provided between said stopper (17) and the driving member (8), a spring (19) for energizing said operation handle (18) toward the driving member (8), at least one engaging projection (31) projecting toward the driving member (8) provided on a surface of the operation handle (18) facing the driving member (8), and at least one engaging stepped portion (37) with which the or each said projection (31) is engaged provided on the driving member (8) on a surface facing the operation handle (18), characterised by there being provided an inclined surface (31a) provided on the surface of the operation handle (18) facing the driving member (8) and inclined toward an axial extremity of an at least one engaging projection (31) in the direction of regular rotation of the driving member (8) so as to bring said inclined surface (31a) into elastic contact with said engaging stepped portion (37) by an energizing force of said spring (19) when said mechanical brake (13) is being operated. A lever-type hoist and traction apparatus as claimed in claim 1, in which a surface of the driving member (8) facing the operation handle (18) is provided with at least one projecting portion (32) engagable in the axial direction with an end face of the engaging projection (31) provided on the operation handle (18) during a rotational operation of the operation handle (18) relative to the driving member (8), the or each portion (32) having an idling-controlling surface (35) brought into elastic contact therewith by said energizing force of the spring (19), whereby the or each said projecting portion (32) is provided with said engaging stepped portion (37) at its rear end portion as seen in a regular rotational direction thereof. A lever-type hoist and traction apparatus as claimed in either of claims 1 or 2, in which an idling-controlling spring (50) for energizing the driving member (8) in the brake-loosening direction of the mechanical brake (13) is provided between the driving member (8) and the operation handle (18). A lever-type hoist and traction apparatus as claimed in claim 1, in which the stopper (17) is connected with the driving shaft (5) by a connecting structure using a large number of concave and convex grooves (17a, 23a), concave portions and convex portions (29) engaged with said concave portions (30) being provided between opposite surfaces of the stopper and the operation handle (18), a plurality of at least ones of the concave portions (30) and said convex portions (29) being provided at regular intervals in the circumferential direction, and their pitch angles being selected so as to be different from those of said concave and convex grooves (17a, 23a) provided between the stopper (17) and the driving shaft (5) and ones obtained by multiplying said pitch angles of the concave and convex grooves (17a, 23a) by integers.

Inventors: INOUE YOSHITAKA, KOBAYASHI EIKICHI, OKAMOTO YOSHIAKI, WADA YASUO, INOUE, YOSHITAKA, KOBAYASHI, EIKICHI, OKAMOTO, YOSHIAKI, WADA, YASUO, INOUE, YOSHITAKA, ELEPHANT CHAIN BLOCK CO.LTD., KOBAYASHI, EIKICHI, ELEPHANT CHAIN BLOCK CO.LTD., OKAMOTO, YOSHIAKI, ELEPHANT CHAIN BLOCK CO.LTD., WADA, YASUO, ELEPHANT CHAIN BLOCK CO. LTD.
Applicants: ELEPHANT CHAIN BLOCK CO, ELEPHANT CHAIN BLOCK COMPANY LIMITED
Application year: 1994
Main classification: B66D3
IPC codes: B66D3